Slip joint for drill string



Sept. 16, 1958 F. L. LE BUS, SR

SLIP JOINT FOR DRILL STRING Filed July 15. 1954 3 Sheets-Sheet l INVENTOR.

BY FL. LeBus, 5/.

Sept. 16, 1958 F. L. LE Bus,- sR 2,852,231

- SLIP JOINT FbR DRILL STRING Filed July -15. 1954 s Sheets-Sheet 2 I II 2 1 2 68 5 4 I 1% Z I 4 I 54 Fig. 3-A

IN V EN TOR.

ELLeBus, 5/." BY

ATTORNEY p 16, 1958 F. L. LE Bus, SR 2,852,231

SLIP JOINT FOR DRILL STRING Filed July 15. 1954 3 She swsheet 3 6 H" i j in I ,if IN MI I 6% I I;VVENTOR.

BY EL. LeBus, 5r:

ATTORNEX SLIP JGENT FQR DRELL STRING Franklin L. Le Bus, S12, Longview, Tex.

Application July 15, 1954, Serial No. 443,593

1 Claim. (Cl. 255-23) This invention relates to improvements in rotary drilling equipment, and more particularly, but not by way of limitation, to a combined slip and safety joint for a rotary drilling string utilized in drilling or coring of oil well bores.

In the rotary drilling of oil wells, particularly deep bores, the drill bit is secured on the lower end of a drilling string which is rotated at the surface of the well through the drilling rig which includes a rotary table and cooperating kelly therewith. The kelly is usually a square shaped elongated member disposed in an aperture in the rotary table for movement downwardly therethrough. As the drill string proceeds downwardly, it is necessary to periodically add extra joints of drill pipe for making additional depth into the well bore. When this is necessary, the kelly is usually moved upwardly above the apertured rotary table, and the additional joint of pipe is inserted between the kelly and a previous top section of the drill pipe whereupon the drilling string is again lowered to begin the drilling operation. In the present available equipment for inserting an additional joint of pipe, it is usually necessary to raise the drill bit, or core bit from the bottom of the well an equal distance that the drill string is raised so that the extra section or joint of pipe may be added to the string.

In the drilling of certain formations the raising of the drill bit off the drill floor has many detrimental aspects, particularly in those formations which are known as gravel beds consisting of hard chert pellets or rocks, both large and small, which have a tendency to become loose during the drilling operation in the well bore. After loosening the pellets or rocks will usually work up the side of the drill pipe and will float around at a height thereabove in the circulating drilling mud. In this condition the pellets do not do any particular damage, or interfere with the drilling or coring operation of the rig. However, during the addition of an extra section of pipe in the drill string, and when the drilling fluid is not circulating as the drill or core bit is raised off the bottom of the well bore, which is usual in present day equipment, the loosened hard pellets will gravitate, or settle through the thin drilling mud fluid to the bottom of the well bore, so that when the drilling or core bit is lowered back to the bottom of the well bore for a further drilling operation, the bit and particularly the cutting face thereof is disposed on top of the hard pellets, or rocks. As a consequence, upon rotation of the drill pipe, the hard pellets usually become trapped in the bottom of the well bore and the circulating mud fluid will not wash them out of the way so that the drill or core bit can contact the formation to be drilled. During a continued rotation of the drill string, the hard pellets under the drill or core bit will start a rolling action that causes considerable damage to the drill bit, or core bit, particularly the expensive diamond core bits so that in a very short time it becomes practically useless.

This invention is generally concerned with an improved slip joint for utilization in a drilling string when it is necessary to add additional sections of pipe to the drill string for a continued drilling operation, and particularly a slip joint that will permit insertion of the additional section of drill pipe without lifting the drilling bit or core bit 01f the bottom of the well bore. It is also well known in rotary drilling that telescopic sections have been used in the drill strings in order to limit the weight applied to the drill bit so that drilling or coring bits would not be subject to enormous weights of the entire drill stem causing a faster dulling, or crushing of the drill bits, and if proper braking power was not applied would have a tendency to cause crooked hole drilling. This invention also contemplates that a predetermined amount of calculated weight to make the bit head penetrate the' formation being drilled at a smoother more efiicient speed of penetration, which is particularly desirable when drilling in deeper bores with long and heavy strings of drill pipe because a driller may vary the weight of a drill string from the braking apparatus at the surface of the well that is subject to the normal inaccuracy of the human element. With predetermined knowledge of the weight of the core barrel, the desired number of drill collars and a partial section of the slip joint the necessary weight for an efficient and regulated penetration may be readily calculated.

It is an important object of this invention to provide an improved slip joint for drilling strings which provides for the addition of extra sections of pipe in the drilling string without lifting the drilling bit from the bottom of the well bore.

And still another object of this invention is to provide a slip joint cooperating with the drilling string in such a manner that the weight of'all elements of the drilling string below the slip joint and including part of the slip joint may be easily predetermined and calculated in order to make up the necessary weight required for the drill bit to penetrate the formation in a more efficient and regulated speed of penetration into the formation being drilled.

And still another object of this invention is to provide an improved slip joint which will permit insertion of an additional joint of drill pipe without removal of the drill bit from the well bore and yet permit operation of the drill bit when the slip joint is in anexpanded open position.

1 And still another object of this invention is to provide a slip and safety joint for drill strings which is simple, practical and economical in its operation.

Other objects and advantages of the invention will be evident from the following detailed description, read in conjunction with the accompanying drawings, which illustrate my invention.

In the drawings:

Figure l is a broken vertical sectional elevational view with certain parts in elevation of the upper portion of a drilling string adapted to be'disposed in a well bore and depicting the novel slip joint interposed in the string.

Figure 1A is a view similar to Fig. l of the lower portion of the drilling string at the beginning of a drilling operation in a well bore.

Figure 2 is an enlarged detail view in perspective of the cooperating spline members of the slip joint.

Figure 3 is a view similar to Fig. 1 showing the upper portion of the drilling string with the control spline, moving slightly off during the drilling operation.

Figure 3A is a view similar to Fig. 3 showing the lower portion of the drilling string for a continued penetration into the well bore.

Figure 4 is a detail view in perspective of the detent latching means.

Figure 5 is a view taken on lines 5-5 of Fig. 4.

Figure 6 is a view similar to Fig. l for the upper portion of the drilling string showing a stillfurther position of the control spline.

Figure 6A is a view similar to Fig. 1A for the lower portion of the drilling string and showinga further drillingoperation into the well bore.

Figure 7 is a'sectional elevational view partly in elevation 'of'the upper part of the drill string vShowing a drilled off position of the control spline when it is necessa'ry toadd an additional joint of pipe.

Referring to the drawings in detail, and particularly Figs. 1 and 1A, reference character 2 indicates generally a drill string adapted to be disposed in a well bore 4, the bottom of 'which is indicated in Figs. 1A, 3A and 6A. A rotary kelly member 6 cooperates with a rotary table 8 normally utilized with a drilling rig (not shown) at the surface of the well. The table 8 in turn connects with the top section of a string of drill pipe 10 extending into the well bore for connection at 12 with an upper sub member 14. The sub member 14 is. connected through complementary threads 16 with a downwardly extending cylindrical housing member or sleeve 18in turn cooperating with a clutch member 20 connected at 21 with an intermediate cylindrical housing member or sleeve 22 to provide structural housings of the slip joint 23. The sleeve 22 is connected by complementary threads 24 to a lower sub member 26 in turn-connected to a core barrel 32. having any suitable type of core drill 34 disposed at the lower end thereof for drilling the bottom 36 of the well bore 4. A suitable safety joint 38 is interposed between the drill collars 30 and the barrel 32 which permits renioval of the complete core when the outer barrel stuck, and is usual practice in the industry.

The sleeve member 18 is provided with a plurality of circumferentially spaced spline or clutch dog members 40 comprisingjinwardly directedlugs integral with the inner periphery of the sleeve 18, and preferably comprises three equally spaced lugs around the circumference, but not limited thereto. It will be understood that any practical number of lugs-may be utilized as desired. The clutch member 20 is provided with an upstanding reduced neck portion, or cylindrical sleeve 42 (Fig. 2) having a. pinrality of circumferentially spaced longitudinal grooves 44 provided thereon. The grooves 44 act as female splines cooperating withthe male splines 40 for a purpose as willbe-hereinafter set forth. The sleeve 42 is also provided with an equal number of grooves 46 communicating to restrict rotation between sleeve 18 and member 20 when the lugs 40'are disposed in the recesses 46 and abutting shoulders 45 during'the lowering of the drill bit into the well bore. When the drill bit is disposed on the bottom of the well bore 4 and ready for a drilling, or coring operation, the ball detents 54 are automatically disengaged from the recesses 58 by a right hand rotation of the sleeve 18 relative to the'sleeve 22 moving the lugs 40 into the grooves 44 permitting longitudinal movement therein.

The sub member 14 has a threaded aperture 64 in alignment with an aperture 66 in the neck section 42 and an aperture (not shown) in the member20. A wash pipe 68 extends through the apertures and is connected at 70 to the sub 14 and extends downwardly through the bores to a point slightly above the sub 26. The lower end of the wash pipe 68 is provided with a female clutch dog 72 adapted to cooperate with male clutch dogs 74'provided on the lower end of the clutch member (Fig. 1)

with and of greater width than the longitudinal grooves 44 providing shouldered portions 45. The grooves :46 have the lowermost portion thereof conterminous with the upper shouldered portion 48 of the sleeve 20. The female splines 44 are provided-with-a tapered portion 47 to facilitate association of the lugs 40 with the grooves 44.

The shoulderedportion-48 as is clearly shown in Figs. 4 and 5 is provided with a recessed portion 50 having a reduced diameter at 52, and in which is disposed a ball detent member 54 supported upon a helical spring 56 anchored in the bottom of the recess 50. The helical spring urges the ball detent 54 upwardly into communication with an arcuately shaped recess 58 provided in the lower rim 60 of the sleeve member 18. A plurality of circumferentiallyspaced balls 54 cooperate between the rim 60 and shouldered portion 48, and as shown, preferably three such latch detents are utilized, but not limited thereto. The latch detents cooperate'with the recess 58 to maintain a locking engagement betweenthesleeve 18 and the sleeve 22 in amanner as will be hereinafter set forth.

The splined portions 49 and 44provide for a telescoping arrangement of the slip joint 23, but the lugs 40 are clutch locked in recesses 46 to prevent any opening or telescopic movement during a loweringof the slipjoint into the bore and the detrimental aspects thereof. The spring urged-ball detents cooperate with the recesses-58 for a purpose as will be hereinafter set forth.

Before letting the slip joint assembly in the well bore with the drill stem and kelly up as shown in Fig. 1, manual pressure is exerted on the top of the sleeve 18 to force it downward against the shoulder 48 thereby pressing the ball detents 54 downward against the action of the spring 56. In this downward position, the splines 40 are at the bottom of the grooves 44 and a counterclockwise, or left hand movement of the sleeve 18 will move the splines into cooperation with the wider grooves or slots 46 so that the top of the male spline 40 will abut against the shoulder 45 for locking the assembly. In this manner, there will be no telescoping or disengagement of the slip joint 23 while it is being lowered into the well bore. -As soon as the drill bit is disposed on the bottom 36 of the well bore 4 the assembly is ready to operate. The drill string and the slip joint 23 are given a clockwise, or right hand rotation causing a rotation of the sleeve 18 relative to the member 20, thereby moving the male splines 40 out of the wider slots 46 into alignment with the longitudinal slots 44 permitting longitudinal movement between the sleeve 18 and the reduced neck portion 42, and then the unit is ready to drill downwardly.

Operation Continued right hand rotation of the drill string drives the'complete assembly and as the bit 34 penetrates the formation the splines or lugs 44 will drill off, or move vertically downward relative to the lugs 40. It will be notedthat the lugs 40 andgrooves 44 have'a limited length of drive contact, approximately two feet, but not limited thereto. This is necessary so-that the operator will have to feed the rotary kelly 6 downward after approximately two feet of cored hole in the bore 4'has been made. A continuous feed of the kelly must be made as the-core bit penetrates the formation further asshown in Figs. 3A and 6A. From the predetermined weight calculation the speed of penetration is regulated to the speed of drilling and the-operator will have to lower the kelly at approximately the same rate as the core bit 34 penetrates the formation'to prevent disengagement of the clutch members 40 and 44. If the clutch members'were as long as the ordinary kelly, and the rotating kelly did' not continually feed after a certain normal penetration had been made, it would not be possible to add additional sections of drill pipe without raising the drill, or core bit off the bottom of the wellbore in which case pellets, rocks, and the like, would fall under the bit before lowering it back to the bottom. Consequently, the operator must lower the 'kelly at approximately the same rate of speed as the core head penetrates the formation and as soon as the 'kelly approaches the bottom of its feed as shown inFig. 7,'the clutch members have drilled olf as shown therein.

"When it is desired to add an extra joint of pipe at the top of the drill stem near the surface of the ground in order to continue the drilling operation, the lugs 40 are moved vertically upward to assure disengagement with the grooves 44 with a simultaneous movement of the wash pipe 68. The wash pipe 68 is several feet longer than the driving kelly or the joint of drill pipe which is to be added, and thiswash pipe can be moved upwardly bringing the clutch member 72 into contact with the clutch dogs 74. In this upward movement, it will be apparent that because of the length of the wash pipe 68, the drill bit 34 is not moved, but remains stationary on the bottom 36 of the Well here 4, thus assuring that no rocks, boulders, pellets of chert or the like will fall into the bore 4 beneath the bit 34 and cause costly damage to the core bit upon resumption of the drilling operation. It is not necessary that the clutch dogs 72 and 74 be in connected relation, but may be so when it is desired to rotate the drill string for any purpose as may be desired, such as a slightly stuck bit or the like. The clutch members permit the drilling string to be raised sufl'iciently so that the slips can hold the same while the kelly is disconnected and an additional section of pipe is inserted. In Fig. 7 the clutch dogs 72 and 74 are shown approaching a connected relationship.

From the foregoing, it will be apparent that the present invention contemplates a slip joint assembly Which permits the insertion of an additional section of pipe in the drill string without removal of the drill bit off the bottom of the well bore. It will be apparent that this is accomplished by a telescopic type of slip joint having a clutch apparatus of male and female splines of limited length thereby necessitating a continuous feed of the rotating kelly of the drill string to assure that no feed-oif between the clutch splines will be accomplished until it is necessary to add the extra pipe. Furthermore, the slip joint contemplates a predetermined weight which may be easily calculated to assure speed of rotation for the drill complementary to the speed of penetration of the drill bit to assure that there is an etficient feeding of the kelly relative to the clutch splines and there will be no drilling in the drill string. In addition, the slip joint assembly is locked during lowering of the drill string into the well bore to prevent telescopic spreading thereof. The locking means are assisted by a latching detent member for maintaining the slip joint in assembled condition.

Changes may be made in the combination and arrangement of parts as heretofore set forth in the specification and shown in the drawings, it being understood that any modification in the precise embodiment of the invention may be made within the scope of the following claim without departing from the spirit of the invention.

I claim:

In a slip joint for a drill string comprising a pair of connecting tubular members disposed in longitudinal alignment with each other, cooperating spline members provided on the tubular members, said splines in one position of the members permitting limited longitudinal movement therebetween, detent latch means cooperating be- References Cited in the file of this patent UNITED STATES PATENTS 1,529,544 Kammerdiner Mar. 10, 1925 1,600,744 Thomas Sept. 21, 1926 1,838,313 Kohr Dec. 29, 1931 2,572,895 Waggener Oct. 30, 1951 2,585,995 Brown Feb. 19, 1952 2,624,549

Wallace Jan. 6, 1953 

